Results 31 to 40 of about 26,635,104 (298)
Lunin-Maldacena backgrounds from the classical Yang-Baxter equation - Towards the gravity/CYBE correspondence [PDF]
, 2014 We consider γ-deformations of the AdS5×S5 superstring as Yang-Baxter sigma models with classical r-matrices satisfying the classical Yang-Baxter equation (CYBE).
Kentaroh Yoshida +5 more
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STUDY OF SYMMETRY IN F(R) THEORY OF GRAVITY [PDF]
Modern Physics Letters A, 2010 An action in which the Ricci scalar is non-minimally coupled with a scalar field and contains higher order curvature invariant terms carries a conserved current under certain conditions that decouples geometric part from the scalar field. The conserved current relates the pair of arbitrary coupling parameters f(ϕ) and ω(ϕ) with the gravitational field
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Higher-derivative f(R,□R,T) theories of gravity [PDF]
International Journal of Modern Physics D, 2017 In literature, there is a model of modified gravity in which the matter Lagrangian is coupled to the geometry via trace of the stress–energy–momentum tensor [Formula: see text]. This type of modified gravity is denoted [Formula: see text] in which [Formula: see text] is Ricci scalar [Formula: see text].
Houndjo, M. J. S. +4 more
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EMERGENT UNIVERSE IN THE CHAMELEON, f(R) AND f(T) GRAVITY THEORIES [PDF]
International Journal of Modern Physics D, 2011 In this work, we consider an emergent Universe in generalized gravity theories like the chameleon, f(R) and f(T) gravities. We reconstruct the potential of the chameleon field under the emergent scenario of the Universe and observe its increasing nature with the evolution of the Universe.
Chattopadhyay, Surajit, Debnath, Ujjal
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The philosophy behind quantum gravity [PDF]
, 2006 This paper investigates some of the philosophical and conceptual issues raised by the search for a quantum theory of gravity. It is critically discussed whether such a theory is necessary in the first place, and how much would be accomplished if it is ...
Zinkernagel, Henrik +2 more
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Charged wormholes in f(R,T)-extended theory of gravity [PDF]
International Journal of Modern Physics D, 2019 Wormholes (WHs) are a solution for General Relativity field equations which characterize a passage or tunnel that connects two different regions of spacetime and is filled by some sort of exotic matter that does not satisfy the energy conditions. On the other hand, it is known that in extended theories of gravity, the extra degrees of freedom once ...
P. H. R. S. Moraes +2 more
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ENERGY CONDITIONS IN f(R) GRAVITY AND BRANS–DICKE THEORIES [PDF]
International Journal of Modern Physics D, 2009 The equivalence between f(R) gravity and scalar–tensor theories is invoked to study the null, strong, weak and dominant energy conditions in Brans–Dicke theory. We consider the validity of the energy conditions in Brans–Dicke theory by invoking the energy conditions derived from a generic f(R) theory. The parameters involved are shown to be consistent
Atazadeh, K. +3 more
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Ghost-free F(R) gravity with Lagrange multiplier constraint
Physics Letters B, 2017 We propose two new versions of ghost-free generalized F(R) gravity with Lagrange multiplier constraint. The first version of such theory for a particular degenerate choice of the Lagrange multiplier, corresponds to mimetic F(R) gravity.
S. Nojiri, S.D. Odintsov, V.K. Oikonomou
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European Physical Journal C: Particles and Fields, 2021 In this work, we investigate neutron stars (NS) in $$f(\mathtt {R,L_m})$$ f ( R , L m ) theory of gravity for the case $$f(\mathtt {R,L_m})= \mathtt {R}+ \mathtt {L_m}+ \sigma \mathtt {R}\mathtt {L_m}$$ f ( R , L m ) = R + L m + σ R L m , where $$\mathtt
R. V. Lobato +2 more
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, 2013 In this paper we review the definition and properties of redundant operators in the exact renormalisation group. We explain why it is important to require them to be eigenoperators and why generically they appear only as a consequence of symmetries of ...
Morris, Tim R., Dietz, Juergen A.
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